NMS systems are employed in a variety of network types to conduct system-level management of the elements of the network. Generally, a NMS performs functions including: alarm/fault management, performance management, configuration management, security management and business/account management. These systems may receive or request information from the underlying network elements, and provide management information to a network administrator through a user interface. A network administrator may also actively manage the configuration of the network and/or network elements through the user interface.
In networks such as Wavelength Division Multiplexing (WDM) optical communication networks, event management, e.g. alarm management, is a crucial function of the NMS. In the case of alarm reporting, for example, any alarms reported by a network element must be accurately reported with minimized latency so that a network administrator may take corrective action. Delays in reporting alarms can lead to unnecessary system failure and loss of network traffic. Inaccurate reporting, e.g. as to the time and/or location of a fault, can also lead to delays in system repair, Service Level Agreement (SLA) violations, and/or unnecessary remedial effort.
Known NMS configurations immediately report all alarms reported by all network elements. A problem arises, however, when reported alarms toggle between states. This can occur in an optical communication network when performance criteria for a network element, e.g. bit error rate, FEC error count, laser current, etc., intermittently moves between acceptable and unacceptable levels, or when a network element is on the verge of failure and generates frequent clearing alarm(s). Forwarding each state change of toggling alarms to a network administrator can cause serious NMS performance and capacity problems, which can even lead to paralyzing the whole NMS through alarm event report flooding. Other impacts include response time degradations, service denial, and overwhelming the network administrator with unimportant information.
Accordingly, there is a need for a system and method for managing toggling events, such as alarms, in an NMS that can prevent performance degradation caused by an excessive number of processed events, while still reporting critical events to the network administrator with minimal latency.